During their residency at the Sphere in Las Vegas, U2 had a surprise guest join them on stage - Lady Gaga. The two iconic music acts performed duets of Lady Gaga's "Shallow" and U2's "All I Want Is You" and "I Still Haven't Found What I'm Looking For". Bono introduced Gaga as the "most audacious, vivacious woman in any room she's ever in", praising her as divine and the vestal virgin of Las Vegas. The performance of "I Still Haven't Found What I'm Looking For" also included a snippet of Massive Attack's "Movie' On Up" with Gaga joining in on vocals. This was not the first time Gaga collaborated with U2. She previously performed "Ordinary Love" with the band at Madison Square Garden in 2015. Gaga has been making guest appearances with other music acts recently, including a performance with the Rolling Stones in New York. U2's residency at the Sphere in Las Vegas has been a success, prompting an extension of 11 additional shows in January and February 2024. The band has not had prominent guests join them on stage until Gaga, but there could be more surprises in store for future performances.